What you have said so far would lead me to recommend a line such as NCL and add $100 to your cruise budget and do some of the alternative dining venues.

Celebrity (In a Solstice class ship), Princess and Holland America would also be good choices. These would be a bit more formal but they have beautiful ships and "overall" decent dining. On many of these cruises they will have lectures on their Alaska, some Mediterranean and longer cruises.

There are many European itineraries that will give you the museums, history and old world charm that you are looking for.

You can also consider doing a Caribbean cruise on one of these lines to see how you like the cruise experience. I would not do anything under seven days. A shorter cruise is a different demographic and experience.

Please come back with more questions that will help us narrow down your needs and expectations and we can make a better recommendation that fits them.

Take care,
Mike

The Celebrity (Solstice Class) ship are beautiful, however, they do not have self serve laundry rooms with irons as Princess ships have great self serve laundry rooms with irons to press everything.

Celebrity does not have any time dining options, Princess does, the exception are the PAY restaurants.

Holland America has mid size ships with cabins around 183 SF +/- for inside with outside Balcony are additional SF for balcony.
Holland America will have more seniors in general and have the most loyal of repeat cruisers, excluding the elite members on Princess, they get unlimited dry-cleaning/laundry along with free internet packages, long voyages allow for light packing. Exceptions are suites, most of the cruise lines offer these amenities complimentary with butler services.

Princess does have two newer ships, the Royal and soon to be Regal Princess.

I actually check the web-site "Vacations to Go" to pull up all the ships sailing the region of my particular interest, then open the links to read the ships features, such as self serve laundry, anytime time options etc.